In a UMTS (Universal Mobile Telecommunications System) network, for the purposes of improving spectral efficiency and improving the peak data rates, high speed packet access based on W-CDMA (Wideband Code Division Multiple Access) has been realized by adopting HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access). In comparison to the call switching mode using W-CDMA individual channels, in HSDPA/HSUPA, a shared channel is used to transmit user information thereby to be able to allocate radio resources with high efficiency and low delay. In order to further increase the HSDPA/HSUPA peak data rates, spectrum efficiency and capacity, specifications of radio interface of a long term advanced system called Long-Term Evolution (LTE) are completed in 3GPP (3rd Generation Partnership Project). In the LTE system, the OFDMA (Orthogonal Frequency Division Multiple Access) is employed for the downlink and the SC-FDMA (Single Carrier-Frequency Division Multiple Access) is employed for the uplink. Besides, in order to share the processing and radio parameters with the downlink, uplink SC-FDMA signals are generated by the frequency domain processing using DFT (Discrete Fourier Transform)-Spread OFDMA.
In addition, in LTE, synchronous detection is employed using a reference signal (RS) of which the modulation phase is known in a receiver (it is called “RS” in LTE specifications though it is called “pilot signal” in W-CDMA). In the downlink OFDMA, multicarrier signals are employed, and RS symbols are multiplexed in discrete resource elements (RE) in time and frequency domains in a resource block (RB) (see Non Patent Literature 1). In the meantime, in the uplink, in order to maintain a single carrier signal, a block in which an RS is mapped to an SC-FDMA symbol is time division multiplexed with a block to which an information symbol is mapped (Non Patent Literature 1). For example, the RS is received by a mobile terminal apparatus thereby enabling synchronous detection of a downlink signal. The RS is subjected to scrambling by a cell-specific scrambling signal (randomized by an existing signal sequence).